Wondering if anyone has been having the same problem. Currently i am unable to buy both the homes at Riften and Markarth. Even though i have completed all the quests for both jarls, when walk up to the jarl in markarth the dialogue option for the house doesnt even come up same for riften. If any knows how to solve this problem or has had it occur please post some information.

Same problem here.

same here, pretty [censored].

You have to be level 20 to get the house in Markarth.

nope, im 22 and still cannot buy it. I got the prompt from the steward, but had no cash, saved up some money to buy it and now the steward wont even talk to me, save the canned three phrases.

I managed to get the house in Riften. For some reason, if you revisit Cragslane Cavern after the enemies respawn, go in and kill them all, it MAY trigger the quest as completed.