I was in a Zep. tribute band for a short time, wasnt as fun as you might think. Also a DMB tribute band, didnt last for more than a month or 2. The problem I found, was that unless your band is absolutely perfect at recreating the original, alot of people will only see you a few times and they will get bored with hearing just one artist's music. The ones that do well usually have alot of money to re-create the whole "concert experience".
The best one I saw was "The Machine", a Pink Floyd tribute. They are internationally known and have the whole package including all the lights and a huge following. Theres a well known Beatles cover band, they even look like the originals. Hair, clothes, gear, etc...
The average bar crowd these days would rather hear songs they know, can sing along with,dance to, and most of all want variety. Unless you have the money to travel all over and can perfectly replicate the band its easier to find one thats already well-established that needs a new member. Or just play covers of different bands, and maybe "specialize" in 1 certain known group. This is only my experience though, so by all means, if you want to try it, I d say go for it and good luck! : )