2 solutions available
1. buy a new cruiser that uses a 1 1/8 head tube (possibly a designer bicycle or maybe even a walmart that comes with a shock, probably a crappy shock)
2. Get someone to braze lugs and a new 1 1/8 head tube onto your frame.
I found a 90's rockshox on Ebay for $40, with the 1" tube.
If you're buying used, make sure the tube is long enough to go through your headset stack and frame and not come short of the locknut. If its too long, you can cut it down with a hose clamp and hacksaw and file, or add keyed washers (find junk reflectors and cut off the tabs).
I've looked around and emailed Rockshox and Manitou. I think
RST is the only one making new modern shocks (entry level, not with the damping and lockouts etc)
for 1" bikes. None of the manufacturers care. But Marzocchi might still have some old crown&tube NOS parts for 90's 1 1/8 shocks like the Bombers. I have a 1 1/8 coil&oil and LOVE IT. It has the old style pinch bolt and snap ring crown, and could be used with a replacement crown. After that they went to press fit (cryo-fit aka freeze the parts and press fit).
I'd like to build a cruiser that I can use a suspension fork on though most that I've seen use 1" steering tube. Can anyone point me in the right direction of Mfg. that I should be looking at??
Need it to be 1 1/8 to use most common aftermarket forks.