With IdeaPads it's just totally model dependent. Some models work great with Linux, some don't work at all.

I really wish I could find anything at all that works well with linux, has at least 4G RAM (better 8 or 16), doesn't have a heavy screen , and is no wider than 28cm. Buying laptops has become really, really difficult. </digression>

28 cm width essentially excludes the 11.6" to 13.x" category, which are typically at least ~29 cm wide.

So you're probably looking at a 10.6" netbook.

Well, I'd probably take an 8G 29cm thing over 4G 28cm, but that doesn't seem to matter much, since I can't find any of either. The small ones all seem to either be tablets with a lightweight attachable keyboard (ie. prone to tip backwards) or they have a locked BIOS and can only run chromeos.