I would give the $4.40 rush a shot. They're not limited to 135 any more, so anywhere from 200-400 people play depending on the time. I haven't played many of these (less then 5), but I have played a good amount at the 1.10 level and at either level the plays is similar. Just a lot of stupid shoves at the 1.10 level.
There's a fairly basic strategy to use when playing these. I suggest watching the Videos in King Curtis post
and reading cardriverx's strategy here (http://www.cardschat.com/f59/rush-demand-sng-strategy-4-40-a-193215/)
KC made the post when they were still at a 135 max, but the videos still show the solid style of play you need to use.
Cardriverx's post outlines everything you need to know.
I think that if you put in the time with these you should be able to get the hang of them and find yourself making quite a few final tables.
Oh, and these tournies finish up right around 2 hours.