Does anyone know where to get good 16" rim which will be compatible with 16" strida hub (24 spokes)? Want to rebuild my rear wheel with stronger rim…
Alex Y 303
http://www.alexrims.com/default.asp
Caution: Different inner diameter - original Strida spokes will not fit (too short)!
Sorry, don’t know if Mr. Eberhardt does have 24H in stock 
Thank you. It is good that they are available in 24h (Alexrims site mistakenly states that they are 36h/48h).
Does anything double-walled exist?
Yes, the Alex site is not very accurate.
Maybe it helps to know that bicycle builders usually are able to order every number of holes they want.
You might also search for BMX bike or Frog rims.
Here is another small wheel specialist:
http://www.gaerlan.com/bikeparts/parts/16wheel/wheel16.html
If you find double wall rims in that size please let me know. 