There are carpet kits out there made specifically for Mavericks. No need to adapt anything. Look on eBay. They are there all the time. Prices tend to run $130-140 A good company is ACC (American Custom Carpets, I think). Price should be in the $230 range (yikes .... price went up!), and the carpet is formed to the floorpan. They literally use old chunks of car floors in their process. Also, since your car has the cat hump, I believe that your floorpan is identical to Granada/Monarch.
if you wanting to go to the junk yard and pull carpet there I'd try a mustang. But, don't see why you'd do that, it'll be better to just spring the $120 for a new one.
Just got some in today from www.auto-interior.com. From the time I ordered to the time it got to my door was less than a week. They get theirs from ACC, just like Auto Krafters, but charge a lot less. Ours was about $125, shipped.
Yep. ACC is the best way to go. Custom, made-to-order carpet, made right here in Alabama. Also got mine from www.auto-interior.com. Took two days from order to delivery (helps Im an hour away from the factory) and it fit like a glove.