Every extra feature comes at a price, and there's only so many models that cost between $300-$400. To gain noticiable improvement in the performance over those models can cost considerably more money.
There's the Traditions Kentucky and Hawken for $330 and $355 respectively at Mid South Supply:
http://www.midsouthshooterssupply.co...54%49%4F%4E%53
The Lyman Deerstalker for $357 and Trade Rifle for $399:
http://www.midsouthshooterssupply.co...41%4C%4B%45%52
http://www.possibleshop.com/lyman-rifle.htm
Considering smoothbores, there's a selection of good quality Indian made reproductions at the Middlesex Village Trading Company that are always interesting to look at and which cost much less than their European made counterparts.
http://www.middlesexvillagetrading.com/NEWmuskets.shtml
There's also reasonably priced used guns like the TC's that can have an upgraded hammer & vent liner installed [the hammer under TC's "No BS" lifetime warranty] or a new drop in Green Moutain replacment barrel added for a reasonable cost. Some TC owners just love their TC flintlocks so much that they won't shoot anything else. Now those are something to consider buying used for a good value for the money. With a Green Mountain drop in barrel the TC's can shoot right along with some of the best guns around for only a fraction of what the others cost.