Innovate LC1 is cheap. Naw is cheaper with a display (14point7.com). It wouldnt be hard to sort out the display business once youve got a controller.
Ive got this
Which ill prob sell shortly for about £50 delivered inc a case. Tis a JAW wideband controller and display. Works with any bosch wideband sensor, can find them off audis in the scrapper etc or i got one new delivered for £32
Tis like the megasquirt of widebands really but its pretty good. Has got pretty decent specs, has the hardware to do datalogging stored onto an onboard memory but its not implemented in the firmware yet