I do telecommute but my biggest obstacle is conducting a Needs Analysis. There are some industries/situations where you have to wallow in the weeds - i.e. be face to face to pull out those obscure business rules by their proverbial roots.
Sometimes the foreman on the shop floor has to show me the widgets with all its variants - how when one widget isn't available, another widget from another family (or families) can take its place IF the customer orders the associated retro-fit kit.
Even if I believe I've done the best needs analysis I can possibly do, there are always going to be followup PMs, emails, phone calls, etc. and as fast as the communication can get from one to another, there is still that latency of people not able to get back to you instantly. Sometimes it's a holdup, sometimes it's situation where you can work on another part of the project.
Right now, I am in the home stretch of a project and I am at the location every other week until we are up and running - once this pig is running and any bugs are worked out, then I can go back to full time telecommuting..... until the next needs analysis....