Welcome to the fold. Generally a happy buch here & I'm sure you'll fit right in.
You like Challenging designs.
Hmm.
There is Heaven & Earth Designs, of course. Or failing that, you could convert your own image using software available on the web. I wanted a challenge but wasn't completely happy with the software available, and ended up writing my own conversion program. Using it, I converted one of my Honeymoon photos, leading to the 28 count picture below:

117 colours...
Or go and use blended threads (converted with the same software to 25ct, but using 151 solid colours to make 118 blends & solids):
Don't think either looks too much like a traditional cross stitch...
Have fun, whatever you want to do, we can both help and learn from you too.
Regards,
Richard.