I didn't check the pricing on the AA (Mark's) gears, but they can't be more than a rock box, orion or extra t-case. OTOH, there's alway the NP203 add-on. They're not too expensive and are a fairly common mod on 60s. Anything you add to the back of the tranny will require retubing the driveshafts, and that's certainly not free.
It's very rare to convert a 62 to a manual tranny, and I haven't seen much or heard much from my friends on details. I'm assuming that the t-case that goes behind the A440F is not a bolt up to the H55F. If it is, then another place to look would be to regear the diffs, as far as cost/benefit. Part of the calculus to that decision is what size tires you plan to run.