Install suspension forks on non-suspension bike I have a 1990s Saracen PowerTrax. Is there a way I can install a suspension fork, or will that muck up the bike somehow? I'm actually interested in ways to raise the bars with respect to the seat, so that wouldn't be a problem. My toes rubbing in the wheel, in the other hand, would definitely be a problem.
You might be able to fit a suspension fork on your bike, depending on frame geometry, but I think it’s likely you will not be able to. 

Frames designed for suspension forks locate the head tube higher to allow for the extra length of a suspension fork, and to provide somewhere for the top of the wheel to go when the suspension compresses. 

In the early-mid 90’s rigid bike’s either had no provision for suspension forks or a ‘suspension corrected’ frame and longer rigid fork that would allow for swapping in a suspension fork. If you have the former you obviously can’t fit a suspension fork. If the latter, there is still a problem because even a suspension corrected frame only allowed for a contemporary fork with something like 50mm of travel. Modern forks have twice to three times that amount.

If you fit a fork that is is longer than the frame was designed for you effectively rotate the whole frame around rear axle and change its geometry. The  head tube angle is increased which can negatively affect the steering, especially of an adjustment in fork offset is not also made. See here for some more information in this. The seat tube angle is also increased pushing the seat rearwards, and the bottom bracket is raised which can affect stability.

Some very inexpensive forks have low travel and may fit, but they are not very functional and mainly add mass. 

It's not a good idea to try to raise the handlebars by installing a longer fork (for reasons above). A riser stem or steerer tube extension are simpler, cheaper and safer ways to do that.