Hellobee Boards

I think you could use glue on wax paper and when it dries glue it to the bottle, then paint it!

Or puffy paint if you want it bigger

I like @Mamaof2's suggestion. You could probably do it right on the bottle if you want. Or maybe find some puffy letter stickers if you don't trust your own handwriting.

I used a stamp and embossing powder/embossing gun for my wedding invitations- you stamp with a special ink pad, sprinkle special powder over it, and heat it and the powder melts and makes a nice raised design. But that would be awfully labor intensive on a bottle. What kind of lettering do you want, exactly?

like this: http://s3.amazonaws.com/cooltools_legacy/archives/hobbyist.web.gif

Seems to me like there isn't a good solution to putting raised letters on the bottles although I think the idea is good. It seems like it would be too small and hard to read.

I would get a larger base and put the lettering around it at the bottom.

ETA: If you use a square base, you could do something like this:

http://www.amazon.com/Fun-Express-Products-Adhesive-Letters/dp/B004MR1S3U/ref=pd_sim_sbs_misc_3?ie=UTF8&refRID=1SNY5FCRAFKD1860SW00

http://www.amazon.com/Fibre-Craft-400-Pack-Stickers-Letters/dp/B001689PXI/ref=sr_1_9?ie=UTF8&qid=1405454561&sr=8-9&keywords=small+letter+stickers

Reviewers say these are tiny - but there arent any actual measurements

ETA: 3/8 of an inch - according to http://www.barnesandnoble.com/p/foam-stickers-400-pkg-mini-dotty-letters/22256684

I've heard of people doing it with puff paint and elmer's glue, letting it dry, and then painting over. Like this: