Since we're on the topic of calculators ... Is there something like Soulver or Speedcrunch, but also handles unit conversions a la google calculator? instacal

Since we're on the topic of calculators ... Is there something like Soulver or Speedcrunch, but also handles unit conversions a la google calculator? instacalc is OK, but doesn't handle units properly either. edit: www.encalc.com seems to do units right, but allowing only one expression at a time is limiting.