Anyone got tips on force-spawning dragons that doesn't involve joining the Companions or doing stuff for the Blades?

Where are you in the main quest? There's a point in the MQ where random dragon spawns will stop. Otherwise, fast traveling in large jumps is a good way to trigger them. I would get a dragon almost guaranteed about every third jump if it was at least half the map, like from Whiterun to Dawnstar (which can be rough on the locals. Better to jump between wilderness locations).

If that doesn't work, start a new game. Really. I had one game where I got hardly any random dragons, in others they rained from the sky.

Well, I just delievered the Horn at High Hrothgar.

have you gone with Delphine to the point you see Alduin resurrecting that one Dragon? (i think the quest is A Blade in the Dark)

i believe Dragons are disabled between the first time talking to the Greybeards and finishing A Blade in the Dark

I just did the Blade in the Dark quest. And I met a Blood Dragon on the way.

really? that shouldn't happen..

are you running any mods?

Had to edit the whole post since you were talking to funnybunny while I was typing on my phone, lol.

Since you finished that quest and had a random dragon on the way, you're not due another one immediately, but they should start spawning. In fact, they should start spawning more frequently as you keep going through the main quest. The fast travel thing always worked for me. It makes a lot of game time pass, and the chance of an encounter increases the more time has passed. (edited again to remove more wrong stuff. I'm tired.)

Well, I have Timing is Everything, which allows me to alter the Dragon spawn chance and the minimum days after a dragon attack.

I just finished that quest.

In vanilla, you will get random dragon spawns AFTER doing the part in MQ called "Dragon Rising".