OK... here is the lowdown on the front input shaft bearing and seal, at least on MY truck... it turned out to be fine after I was able to check it when the G56 transmission was removed from the truck.
At first, however, I was VERY concerned about the bearing, as there was about 1/8" of side to side play at the front of the shaft in EACH direction.
I was starting to source the part locally, in anticipation of needing to replace it, when also in an inspired moment :-laf, I realized that the bearing and seal were likely covered by my MaxCare warranty (even though the clutch I was installing was obviously not).
So I then loaded the transmission onto my freinds truck and drove it on down to my local, excellent and accomodating Dodge service manager.
His diesel tech looked at it and indicated that this amount of side play is NORMAL because when the transmission is removed from the truck, the tip of the input shaft is NO LONGER SUPPORTED by the OEM bushing in the DMF and thus the ENTIRE input shaft is supported by only the one bearing at the back of the bell housing, which also (duh?) happens to be in the middle of the shaft length , so therefore the side to side movement in front of of where the input shaft exits the bellhousing, can NOT be avoided... there is no physical way that a SINGLE bearing located roughly in the middle of the input shaft can COMPLETELY eliminate any side play AT THE END OF THE SHAFT...
In other words, SOME side play of the front input shaft is inevitable when the G56 is removed from the truck !!!
When the G56 transmission is installed in the truck, the front input shaft is also then carried by the bushing insert at the center of the DMF that Dodge uses, ( or the roller bearing in the center of the SMF that SBC uses) and these TWO points of contact are what eliminate the side play that I was feeling at the front of the front input shaft.
This diagnosis was then also confirmed by a reputable transmission rebuilder in the same town, who actually would have jumped at the chance to rebuild the transmission, as his shop is slow right now, but he also independedtly confirmed that the side play of the shaft was normal with the transmission removed from the truck.
STILL not wanting to reinstall a transmission with a bad bearing, and still SLIGHTLY doubting the facts, I then called tech support at Standard Transmission Rebuilders in Texas. They also indicated that side play was more an issue ONLY if it was being caused by the input shaft bearing wallowing out the aluminum casing of the G56, OR from the bearing actually going bad, OR from the bearing overheating and drying out (another way of going bad)... . or from the case stretching and allowing the bearing to move around, thus wallowing out the case even more, or anything along those lines.
Which was NOT the case in my transmission case...
In fact in my g56, upon closer inspection, the bearing appeared well seated in the case, the center hole where the bearing seats in the bellhousing was round and not deformed , nor were there was ANY signs of overheating at the bearing or seal,
ALSO IMPORTANTLY, there was NO input shaft bearing noise or roughness when I spun the shaft by hand!!! It actually turned SMOOTHLY and quietly (ignoring the relative sound of whatever transmission mid shaft was also turning as I turned the input shaft,,,,
FURTHERMORE,
There was NO end play (in/out) of the input shaft
ALSO there was NO weeping or leakage from the bearing seal...
ALSO, there was NO leakage or weeping from the rear main engine seal...
So with no hesitation, I finished installing the transmission in the truck with the new SBC Con-OFE clutch kit !!
The truck is back together, I took it for a short spin into town, and it shifts quietly, smoothly and effortlessly, with only a tiny, little more clutch pedal pressure then before Oo. Oo.
I DID install the TransCoolers and add the extra quart of fluid, though I still used the factory approved ATF+4 until the warranty is up, just in case the bearing or seal starts to go bad in the next 25k of warranty period... then my dealer will have to fix it!! Next time I require a fluid change, after the warranty is up, I'll be sure to use the Pennzoil Synchromesh that Standard Transmission is recommending for the G56.
I'll post a write-up of the Clutch install elsewhere...
I actually STILL need to fabricate an inner shift tower boot to keep the ATF+4 from leaking, because OF COURSE, like other on TDR have experienced, the inner orange, silicone boot that seals bewteeen the top of the transmission and the shifter shaft is torn and slightly leaking. . it's a $140 oem part that I hope to replace with a $20 CV silicone boot (unsplit type)
I DO hope that this post helps clarify what seems to be NORMAL input shaft side play with the G56 transmission removed and what is unacceptable side play in the front input shaft of the G56 when removed from the CTD...
Attention: TDR Forum Junkies 
