Interesting new product from AndyMark: linear servos. They are available in both 150:1 and 35:1. The 150:1 has a max force of 250N and the 35:1 a max speed of 35mm/s. Looks like a good replacement for something like a DART in lower-load applications. The DART can provide around 3.5x as much force, but costs over 4x as much.
The L16-R s only cost $70 each! But will they be legal?
150:1 :
http://www.andymark.com/product-p/am-3516.htm
35:1 :
http://www.andymark.com/product-p/am-3517.htm