MX boots are not the most enjoyable thing when not riding MX. I just bought and then returned a pair of Sidi Adventure Rains because I thought I could live with a boot that offered that kind of protection. Mind you, the Adventure Rain boots are not full MX boots. They are intended as a crossover boot, but they crossed WAY too far to the MX side for my street riding and commuting. Downshifting was an absolute chore. With little to no ankle flex and s stiff sole, you can't raise your toe and that means you have to lift your foot from the peg and mash the shifter down. If you're standing on the pegs, maybe this isn't such a big deal, but it is to me.
Another consideration is how easy they are to take on an off. I know you said you'll be carrying shoes, but honestly that isn't as easily done as you think. For instance, if you are just running into McDonalds, would you change? How about a stop at the grocery on the way home? Walking in tall ski boots with no flex is clumsy and uncomfortable.
I'm not saying not to do it, but I am saying that unless you are riding motocross, you may really hate MX boots and you will have wasted money that could have gone toward boots that actually meet your riding needs.
Morton's BMW is having their Octoberfest open house this weekend. I know they have some boots that will be on a sale rack. IIRC, they have some older model BMW boots that are going well under retail. Sizes may be small (there is a reason they still have some of them). They also have the BMW All-Around which are great boots for about half the price of the top end touring boots. They are still beyond your budget but maybe you can find something you like. Come on down. I volumteer to work the used bike tent so stop in and say hello.