Finding an Arai drum brake is going to be a little tougher but probably do-able. However the Magura Rim brakes are decent brakes and new HS33s (which are the best of them currently though you can get 22s and 11s) as well as aftermarket pads from KoolStop can easily be found and with good rims you will have excellent stopping power
I really wouldn't try for any disc brakes unless you find a frame builder willing to take on the project. However a new front fork should be something you could find I don't know the specs of it but it looks like this website might be of some help:
Vision Recumbent Bicycles: Guide to bicycle models and versions