Are there any

[Acidic Saint]

Companies that sell brand new old school type bmxs full.
Sorry to bother

[CD17]

Its no bother at all 

Yes it depends what you are after, SE do retro Quads & Rippers which look like Old Skool, but are New Skool, also Haro & you can get a Burner.

Or are you looking for a real old skool bike 

If so then have a look in the for sale section in here or on Ebay, there are lads 

[Bob_Acid]

Mongoose, Redline and now Kuwahara have done retro bikes