Well, here goes.
Sights.
For iron sights, TechSIGHTS are the way to go. M16 style arpeture sights at an affordable price. Tough, too.
Scope: Whatever tickles your fancy. Picattany rails are available, as well as standard rails. Whichever one, however, use a bolt buffer. I found that without the buffer, my 10/22 would shake loose even locktite on the screws.
Barrels
Green Mountain makes affordable, accurate barrels. I'd look into them first.
Stocks
As far as a bullpup stock goes, I'd go with Dixie Consolidated. Muzzlelite stocks are crap.
Before buying a stock, review it at Midway USA to see what others are saying about it, if possible.
Action work
Needs some trigger work. A target hammer will suffice. Extended magazine release is also a must.
Magazines.
Stay away from Ramline. Factory mags are good. Butler Creek hotlips are usually decent. Best aftermarket is Tactical Innovations, I think. They make polymer and aluminum mags, at $30 and $60 respectivly. Some find that aftermarket high caps will not feed reliably with match chambers on bull barrels. The Tactical Innovations mags are adjustable for feed angle, etc, to solve this problem.