Commute bike thoughts

Some random thoughts on commute bikes. Lately I've been commuting on my hardtail mountain bike outfited with a rigid fork. It's ok to commute on. Sometimes I go to work on gravel and the fat tires are nice. But for the most part it is a little slow. I've tried slicks and just didn't like it the feel of the 26ers with thin tires.

On the other hand I have commuted a few times on my road bike and it's definitely faster except I can't track stand on the road bike at lights.

That has been a function of how I learned to track stand, and I basically have the wrong foot forward in relation to how I turn the front wheel. With toe overlap as I have on my 700c road bike I clip my toe during a track stand. My road bike is too nice to commute on regularly, I would never want to leave it locked up outside. I feel somewhat bad doing that to my hardtail right now.

I've been thinking about what the best choice for a commute bike would be. I had a cross bike a few years ago that had a surly dropout which has horizontal ends with a derailleur hanger. I didn't do the geometry right and it just never seemed to feel right. I tried outfiting it with a flat bar, but that only felt right when climbing all other times it felt too scrunched up. Tried a super long stem and that just threw the steering off.

Several options I'm considering.
1)find a road bike with similar geometry to my current road bike. Considering that it is a custom built road bike with custom geometry this is a little harder than it sounds (seat tube 49.5, effective TT 51.5, upsloping top tube, 73/73 geom)
2) get road bike with a 10mm longer top tube that what I have and put a flat bar on it with similar stem size to what is on the road bike. This is a little more doable because my top tube was shorter than normal road geometry - the problem is that the seat tube might be too all).
3)getting a cheap 29er mountain bike frame and putting road tires on it
4) getting this conversion kit that lets you run 700c wheels on the 26er and set the brakes up properly

I think the concept of single speed is good. But I won't do that stictly because it is just such a hipster fashion thing right now. If I did though it's a little hard to find road bike geometry because everyone is making theses track bikes

I sort of think that drop bars are a better position for commuting on. It just seems that the flat bar on smooth roads places more pressure on my arms. Off road you are always dynamic moving around shifting weight all over. Drop bar riding in the hoods with a slight bend in the elbow seems takes more pressure off the triceps.