Ex Pres 

EDIT: frame set only
Unfortunately, no pics yet. I've only had a brief glance. This has orange/red tubes with yellow panels and headtube. with the last year of the almost odd TREK downtube decals.

Appears to be in good, not excellent, i.e. ridden but kept-up condition. Trek decals still there, but the Columbus dove decals are about worn off, to provide an idea of condition.

eBay current and completed listings of TX900, 930 and all the iterations up to 970 provided all of one frameset as guidance, so not much help there.

Appears to be either a 56 or 58, so Columbus SL tubing, not the SP in larger frame sizes.

(I will not be interested if it turns out to be a different size, in case any of you might be)

Any thoughts?

nesteel 

TX900 framesets are going for less than $500. (I just had this discussion this week with someone looking to sell me a 60cm frameset, rough paint, no serial (ie: employee built personal bike, so hard to prove lineage. Person thought offering it to me for $500 was doing me a favor. I passed on it) I've seen one or two big ones sitting unsold.
In the last 16 months, I've purchased a rolling 93X (second rate off brand components, nice frameset), and an '81 957 (rough original Campy SR, rough repaint (by Trek back in the day after frame repair). Paid $200 for the 93X, and $400 for the 957. I felt comfortable on those prices given condition.
In better shape than I've described, I could imagine paying up to $600 for a 970. I have been accused of being a cheap skate though.

bikemig 

These bikes don't come up too often. I paid $350 for a complete 1978 TX 900 in rough condition with most of a Campy NR group. I thought the price fair. Also I wanted the bike. If this is a bike you want, you may not get a 2d chance to find one of these.