I have done all the requirements, I have done very possible Solitude quest. The option to buy the house used to be there and now it's gone (I couldn't afford it at first)

But for all you nit pickers out there, here is exactly what I have done

Cleared Wolfskull cave
Defeated Potema
Taking Toryggs horn to the Shrine of Talos
Done the Thieves guild quest for solitude
Done Bards College
Mind of Madness
Helped everyone who needed misallaneous help

As I said before the option used to be there. And now it's gone.

Now the ONLY thing I realise is everyone in the blue palace seems to be angry at me (Milk Drinker, My blood boils) i haven't done any civil war quests yet. The only thing I have done is I killed Bryling in her home for her outfit. I didn't get a bounty. But that was so long ago now.

So has killing bryling really somehow bugged the buying option?

Hi, Ozone, I didn't know who Bryling was so I looked her up. Nice outfit. Since I'm already thane & have proudspire, my favorite home, it might be safe to kill her for it, lol, but I far prefer my handcrafted dragon armor with double enchantments.

I developed a theory 6 months ago, while struggling through the PS3 version of Skyrim, that killing named NPCs outside of a quest will probably eventually cause a problem so I always advise against it.

I should think killing a Thane would put you in everyone's bad books, you seem to have worn out your welcome in Solitude. Perhaps there is something left you could do to recover good standing? Or can you go back to before you killed Bryling, become Thane, buy the house and then kill her if you really want her outfit.

milk drinker..

Ok, I went and killed Bryling, and Irnskar Ironhand (her husband?) as well since I wanted no witnesses, yes I got the nasty comments from my previously adoring fans. I also get a letter from the other Thane Erikur, saying he knows what I did but would not tell, which was a bit worrying. My character is already Thane and already owns Proudspire Manor, but I would assume their hostility would have stopped me getting the house if I did not already have it.

Edit
It quickly seems to have worn off though, I went back and they all seemed fine, if not precisely as glowing with praise as they used to be.

Thanks for the suggestions. I managed to find a workaround to get into proudspire manor (I needed the Stone) by pickpocketing Fletchers key and opening the back way into the house.

I think Erikur is dead in my game also. I recently did diplomatic immunity and he has disappeared completely (I stealthed the whole quest so there was no opporunity for him to fall to violence)

I might do the civil war and see if that does anything