I have compression fit BNC connectors for both RG6 and RG59. So that's not an issue but you make a very good point about the flexibility of 59 vs 6.

The cables won't look unsightly if I splice and run separate power. The splices won't be visible and the cable will be hidden as well.

I have the butt splice connectors for the power but I usually solder and shrink those types of connections.

I came up empty from all of my usual suppliers for extension cables under 100ft. I looked at the cost of 500ft of RG59 Siamese and it's not as much as I thought but I would still have 400ft that I'll likely never use.

Well, I guess I'll have 400 ft of cable I won't use. Anybody in the Caledon area want to buy a partial roll of Siamese cable?!