Since you can weld, the possibilities are endless:
1. Chopper forks, Ape Hanger handlebars
2. Custom exhaust header (paint it with silver header paint.
3. Expanded metal over delicate parts
4. Spikes on any flat surface
5. Whitewall Cheng Shin tires.
6. If not chopper forks, some of those curved lowrider bike springer forks. (I'm actually thinking of putting a motor on my lowrider bike.)
7. High-backed seat.
8. Little skulls on all the bolts (oh, wait, you want something that's NOT overdone)
9. Motorcycle gas tank.
10. Some paint couldn't hurt.
11. Maybe some marker lights.
Although, I've been known to have some odd tastes as far as customizing things.