I ended up using http://www.bartenderbarcodesoftware.com/ to create the stickers, intercepting the request to the printer with WireShark, then finally re-creating the request using PHP sockets.
Nice - I'll take a look at fortrabbit. Your MYSQL Add-on pricing seems a little steep between 64mb and 512mb. Shame you do not have anything in the middle.
Shame that I have a wait to have a quick play. "Yeah! You will get a free slot in 5-7 days"
Viaduct looks promising but no pricing information.