I"m in a similar situiation as you. I started an excavating business last year as a "side" business. The dream is to do full-time, but the reality is you gotta make sure you can pay the bills.
Just the other day I was having a conversation with a well-established contractor who I was introduced to about how to expand my business. He used to be in the excavation business, but moved on to do finished carpentry. The guy is pretty successful, and now has a 15-man crew doing finish carpentry for large-scale commercial contracts. Built it up from just himself to where he now routinely turns away contracts in the six-figure range due to too much work, so I believe that the guy knows what he's talking about.
His comment to me was "Everybody already has a excavator that they use, but they're probably not happy with them." The challenge is to understand why they're not happy and figure out how you can develop a way to differentiate yourself from the rest. His other piece of advice was to move towards the "finish" end of the business: finish grading, new lawn installations, and lanscaping.
A common theme I've found around here is that lots of guys just want to show up with their machine, unload, and start slingin' dirt. They don't want to get off the machine for any reason. If you need something else done, that's your problem. I'm trying to exploit that by offering more of a "turn-key" service for site work. I handle all the logistics, materials, and installation for things like french drains and storm water management. I'm also building a relationship with a landscape architect so I can come in and offer a complete service for site reclamation. Everything from lawn installation to retaining walls. Again, I'm trying to offer a complete service, and not just be the guy who comes in and pushes the dirt.
Will it work? Only time will tell. So far I have one good contact who I've done some "basic" dirt work for. I did the digging, but he did everything else. I pitched my "service" model to him, but he already had everything in motion, since he was used to working with his old excavator. He was happy with the work and with the price, so on the next project, he's willing to try my model. I'm working on developing a second contact now.
Good luck in whatever you decide, and care and be safe...
Joe