I think it is a fascinating situation.
While I agree that you shouldn't have players finding that much money that early all the time, a one time deal, especially at first level, leaves all sorts of interesting possibilities.
No matter what magic they might get with that much money, for instance a kick ass weapon, they are still first level.
It is really a matter of desiging challenges for their abilities, be they from level or items, from having a stronghold to being penniless.
I rather like it from the standpoint that it isn't a regular, standard, start 'em off at first level and have them bow and scrape their way to getting anything until they are much higher level situation.
It even gives me an idea for a new campaign, where all the PCs are rich nobles who decide to become adventurers for one reason or another. It changes the flavor of things immensely - it isn't about getting gold, because they already have more than they need. It is about something else, then. And just because you have tons of money doesnt' necessarily mean, for instance, there is a staff of the magi to buy.
Maybe instead, each character sits with you and comes up with a very personalized set of equipment, magical or otherwise, such that they'd not really be interested in buying more magic anyway. Maybe some of it is even level dependant, so it grows with them.
It would make for a very different flavor of a campaign, and having played and run in so many, different can be quite good.
Think along these lines and I think you can generate quite a bit of fun in a non-cliche way - because after the 10th campaign, characters killing dire rats and scraping up the cash just to be able to afford an identify spell starts to become just another cliche.