There are a few wheel makers, I'll let those who have dealt with some of them chime in here. some have had good luck with having their wheel centers cut out and welded onto new rims. My reply is more towardsyour stated goals of M725 on 44s, especially on the cheap.

1 - not much can be done with these things truely on the cheap. They have a lot of uniquities (I think I just invented a word!) that makes it a bit pricey or labor-intensive to modify, especially axle and suspension stuff.
2. - the 725, I hear, is a bit "nervous" laterally to start with. Lifting it and installing bit meats will exacerbate this. Creepy at best, dangerous at worst. If someone can refute this and encourage dsal45 to proceed, please do so.
3 - the 4-corner drum brakes are not power assisted. They are ok with some increase in tire size, but pedal effort needed to whoa 44s may get a bit excessive.
4 - I don't want to discourage you from building the truck you wish to have, more, I'm just pointing out some things that have already forced some mid-build-up project abandonments. It's pretty easy to get so far easily, then hit a bug wall mid-way through - if you are on the cheap, this wall comes pretty quickly.

Welcome to the zone dsal4. We're all here to help, even if only by way of words of caution.

bob