I’ve recently set my titanium hardtail up with a rigid fork:
It’s a Titus Fireline Evo frame. You get (got?) them from Planet X. Were about £600 new and go for £3-400 second hand.
I really like it – build quality of the frame is great and it is extremely light.
That bike is 10kg on the nose with a dropper, pedals, mudguards and waterbottle cage. Nothing superlightweight on it either – Hope wheels and brakes, 1×10 XT.
The geometry works well for a rigid bike – it’s a few years old and was kind of an XC/trail bike then.
I had been running it with a short stem and 140mm fork (I think it was designed around 100mm) and it set the angles up nicely for an all round trail bike. Since I got a full sus enduro style e-bike that I use for most trail riding, this is now my long distance/local stuff/bikepacking bike where the steeper head angle is better.
Waltly Titanium in China will make you one – even a Stache copy (they build the frames for Travers and many others) This is my titanium 29+ – custom means I could use the right length of fork, rather than putting a stupidly long fork on to compensate for suspension.