Ok, since I'm going to use a DS18B20 for measuring temperatures and a 433MHz RF transmitter to send data to a base station, I'm going to need a OneWire library for the Temp and a VirtualWire/Manchester family library for the TX.
I've already tried VirtualWireTiny and a couple of Manchester Libs but without success 
I know porting an ATmega328 lib to work with an ATtiny85 is not always streamline, still it doesn't look to be extremely difficult either. I wonder if someone has already approached the task of such a port in a more consistent way. A few guidelines could be of much help for anybody wanting to try and do it by themselves.
This is the ATmega328 TX module prototype:
I'd like to make it work with an 8MHz internally clocked ATtiny85, hence reducing even more size and components. I'm positive it can be done 