One other possibility is to purchase a couple of platform steps - the kind made to sit under your entrance way step. These are very solid, and run around 50 bucks a piece. That would raise you up, once the bike was up, so you could maintain control.
Second item is, I'm not sure about your riding habits, but you need to train your self to use your first 2 fingers on the brake, and your last 2 fingers around the throttle. This way, you can run the brake and the throttle at the same time, having enough RPM to move the bike up hill, but dragging the front brake to prevent it from rolling back down. The amount of brake and throttle can stay the same, and you just slip the clutch to make the bike move forward. I learned this from riding in stop and go traffic in downtown Chicago, so it was second nature to use the same technique when loading the bike. You can also do this with the clutch, so you have full grip of the bars. This allows you to stop midstream, and step up onto a platform step, so you are at the right height.