It could be done with some short travel forks but as others have said will be a pain to get right probably.
Ebay will be your friend when looking for some I'd imagine.
Also not sure what brakes you have (disc/V brake) but there's that to consider.
Dependent on your skills and tool collection you'd need a fair bit or a bike shop, may not be cost effective.
I went the other way, replaced knackered suspension forks with some 29er specific rigids and much prefer the ride now for commuting/shopping and the occasional off road tracks.
May help if you suggested your reasoning behind it 🙂