We did some crossband with HT and drone. It worked but the "paid people" wanted inband for compatibility since we mostly have singleband radios (apx6xxx series). It was used during a SAR drill and was a way for routine check ins from teams at intervals rather than 24hr operation. It was a way to get something on the air quickly while scouting for locations for a suitable place for a repeater. For interop, FM is still the common denominator for many. Locally we use xpr8xxx series repeaters (cheap) mostly in FM. Sometimes we put the whole thing and antenna in a bucket truck or even top of a ladder truck ladder. We construct simple sub 50' masts on hill tops, water towers or anything else sticking up. While certain types of coax do better on a repeater than others, we had so many problems that we just carry 1/2" hardline which is a ***** to handle. If you have followed my other disastrous post then you know that our Task Force people statewide are investigating DMR. Not truly sure of the rational at the top or how far they will go with it. I am the guinea pig for many of their ideas and field test/break bunches of their stuff. They like the TDMA efficiencies and lower cost than P25. As to robustness many PS agencies around the country use DMR in spite of moto full court press to push them into P25. Motorola has firewalled DMR from P25 to in their opinion enhance profit. P25 is mostly used by government spending other peoples money so the price pushback is not strong at all. DMR being commercial is definitely subject to cost benefit analysis of "for profit" businesses and individuals. It all seems immoral to me. I have slowly been moving to Kenwood radios which can operate on DMR and P25 in the same radio. The portables are not multiband as of yet which is a negative. I like that I can knock an advanced system key out of my personal radio by just overwriting codeplug as opposed to sending my APX to depot ($400) to delete ASK.
Of course what I would really like is military radios (not happening due to costs and waveforms not legal for anyone but military) with their mesh network capabilities and vast data carrying bandwidth. I've used the FalconIII systems before courtesy of NC Air National Guard and lust doesn't begin to cover my feelings. Tetra and other TDMA (DMR) obviously can do a really skinny mesh and that is attractive if it works predictably.
The moto SLR1000 is 10watts, 10lbs, could run on battery and could be used without hardline (stick the antenna on it and put the whole kit up in the air). I told them I'd check it out.