They do, and as a matter of fact I was quoted one at one of the truck cap/acessories places here in town. They were cheaper than the "name brand" snug tops and such. If I recall the quote was less than $1000, like $925 or so. There was another generic I can't remember the name of I was quoted around the same price at another dealer.
Anyhow, I'd LOVE to see a picture of one on a 05+ Tacoma as I really really need a cap despite the fact I really don't want to grampa my truck up. I think it's just gonna have to go that way cos I halu around expensive music gear unprotected from the elements and thieves way too often.