I had a Crusoe based ultrabook during college (2002ish-2005). Performance wasn't fantastic, but it was a third the size or less than most people's laptops, and I could get 8-10 hours out of it. I didn't even take my power cord to school with me.
Transmeta also later developed Efficeon which had a number of improvements over Crusoe (Hypertransport instead of shared PCI bus for chipset interconnect, larger cache and VLIW instruction length, SSE extensions). HP used it in some of their thin clients. A few years ago I compared it to VIA C7 http://fijam.eu.org/blog/benchmarking-transmeta-efficeon/