I hear you, and understand that you don't want to bring a huge PC with you on stage with all the wire and crap... However, plugging a PCI card to a laptop may not be possible. There are several solutions for musicians nowaday, such as slim PCs (small keyboard, LCD flat screen, slim rackmounted case, wireless keyboard and mouse). My advice would be to get one of those, or to build it yourself (15 inch LCD panel, rack mounted PC case, wireless keyboard with less keys possible, wireless mouse or optical for less hassle, a Creamware LUNA or Scope or Pulsar II PCI DSP sound card for all the mixing, MIDI, I/O and FX all in one).

Good luck