I don't have either sat service right now, so I have no axe to grind.
First, I wouldn't put too much worry into the Fox thing. All services are having these negotiations these days, and they often end up with loss of channels. It never lasts more than a couple of days, and then a settlement is reached. If Fox goes, it will be back before you know it. However, a provider switch is a 2 year commitment these days.
As for extending programs, it is fairly simple to do with the DISH DVRs, as well as the ones from most providers. When you set up the program, you can select the end and start time. After it has been scheduled, there is generally an option to adjust start/stop times.
I currently have TW Cable, and had Comcast for the previous two years. To be frank, I wish I could go back to DISH. However, if the TIVO is the sticking point, you might want to consider going back to cable. Prices are usually a bit better when you are able to bundle internet and phone. The cable services will work with the latest TIVOs.
A lot of the frustration with cable services is with the garbage DVRs that are provided. You can buy a TIVO these days and have it connected to the cable service. That way you get the TIVO guide and all the TIVO features.
In fact, their latest promotion will put a TIVO in your house for about the same price as you will be paying for the cable company's DVR. check out
TiVo Premiere: much more than a DVR - TiVo and cmpare it to your local cable company. The current TIVO offer is $20/mo and a free box with a 2 year commitment. I am currently paying $17/mo for my TW Cable HD DVR and seriously considering the switch.