Need a Recumbent Exercise Bike for Someone with Back Problems?

Can anyone recommend a recumbent exercise bike in which the seat backing can be adjusted to either an angle or upright. My wife is looking for one but suffers from extreme back spasms and feels more comfortable in a seat with a near vertical backing. Thanks!

WE HAVE A PRO FORM ( SEARS ) AT A SLIGHT ANGLE . NEVER SEEN ONE WITH ADJUSTABLE ANGLE ( WOULD BE NICE THOU ) , BUT YOU CAN BUY A WEDGE SHAPED CUSHION AND MAKE IT VERTICAL . HAPPY HUNTING