That's a perfectly acceptable strategy
Actually, having looked it up, turns out that IS by design from MB. I always assumed the rules allowed you to use agreed upon markers to sub for houses if you ran out, but nope.
But the other rules my family played by...
All monetary payments are to be rounded up to be divisible by 20 (IE, $20 is the smallest denomination of cash, eliminating a lot of paper)
Using 4 dice instead of 2, with two pair needed on a roll to go again, and 3 of a kind goes backwards and gets the "middle money."
Oh yeah, the "middle money." There's always a minimum of $100 in the middle of the board, and all taxes, fees and bail goes into the middle. Landing on free parking also gets the middle money.
Any unowned property that is landed on, but not bought, is immediately brought to auction by the bank with no reserve - but the person who declined to buy it can't bid.
Players can choose where they start, and you get paid when you leave go, not when you land on go (unless specifically told to do so by a card).
Players may only build houses/hotels at the end of their turn (to alleviate buildup-roll-hit-selloff turns)