MIMF

I made a thru neck electric guitar with a maple thru neck and mahogany wings with a kauri top. My concern is the back of the guitar which has a maple center section and mahogany wings. My plan is to us Elm Burl veneer which I have, glue it on (very thin veneer) and then have a design laser etched into the Elm burl veneer. since this gets alot of wear and that the laser etching is actually burning the wood, want to use a slow wearing sacrificial barrier finish, in other words be able to use the guitar and re-new the finish as needed. It needs to be transparent to see the design. I have no experience and I do not know if the elm burl needs staining prior to finishing. Any ideas?

My first consideration would be that the elm burl might be too "busy" a background for your lasered design to display coherently.

You'll want a hard finish and if you aren't into spraying you could consider a bar-top finish that's more or less self-leveling and maintenance free. It needs a flat surface with sharp boundaries so that it doesn't just dribble down the sides of the guitar. Generally you build up some kind of dam with tape around the edges and then pour the de-gased, mixed epoxy into the middle and let it flow out around the edges. You need to keep the guitar absolutely level and let the material cure for 24-48 hours in a warm room before you handle it.

Michael Gurien's company in Seattle has experience doing this (laser burning) so we are going to do a test burn. Likely I will just glue some veneer on plywood first, good point. I will look into bar finish, don't know where to get it, but google is my friend. Need something tough like that which can also be renewed when needed.

I'd say polyester is the absolute most durable finish, if that's what you're looking for, but any scratches are very chalky and obvious, and it's difficult if not impossible to renew without it being obvious - witness lines and such.
David's suggestion of a thick bartop finish is probably your best bet.

System 3 "MirrorCoat" is one brand I've used.
http://www.systemthree.com/store/pc/MirrorCoat-c13.htm

Great idea the company system 3 is about 90 min drive from me.