Thanks so much everyone for the great advice!

Rest assured- he's put in as much time on cross-country skis this winter as I have on tele. (I'd actually taken some tele lessons and bought skis a few years back- so I had that equipment and didn't really need instruction. I have a more 'careful' style and am slower, but we're still able to ski together.) It also turns out that my old road bike (a Trek 5000 with a top tube that's way too long for me)- fits him very well- he's 2-3" taller but his proportions are different and it seems to work for him.

I appreciate all the comments re hardtails vs suspension- I think I'm just not ready to get hardcore enough to think about full suspension though (even if this is as much about perception as reality).

I have enough bikes in my garage that don't fit me (reach is too long- even after changing stems/ seat position etc) to be pretty frightened of any stock bike that's not WSD. I realize that every bike is different, but I think I'm unlikely to find a good fit on a non-WSD bike.

I've been watching ebay pretty closely- but after one experience with a seller who was very willing to answer questions (only not the ones I'd asked) about fit- I'm thinking I may be better off spending a little more money and going with the LBS.