Put this on a thumbdrive and use it to test prospective laptops in stores.
http://www.thesycon.de/eng/latency_check.shtml
It's not foolproof but it will give you an idea.
I'm betting some netbooks work fine even with realtracks.

I'm not sure where in the world you live, but Costco here lets you pick up a PC and try it for 90 days, and return it if it doesn't work out. I don't know of any other place to buy with such a handy return policy.