I think making small runs of smaller more basic parts would be a good idea. The jaf bash rings were popular until people found out they were weak. Looking at ideas like that and improving them could be a good way to get your name out there. Offering custom frames and forks alongside that would also be good. Like Greetings said, there are always people out there looking for custom frames. Jaf again was doing alright with custom frames for a little bit until people started having problems with his workmanship. Improve on that and you should do well. You're in a good position really if you've got contracts for other things and can do this on the side so to speak.