Greg like Jody says you just need to go to a country that stamps rather than needs full page visa stickers. A stamp is only
***
of a passport page and most countries immigration will put them anywhere that they will fit. Malaysia is a good choice. Myanmar is also just 2 stamps if you are doing a land border bounce
If you were REALLY full to the point you didn't have room at all, or only for the Thai exit and return, Hong Kong does not stamp at all.