Have you thought about making your own?
If you purchase a pre-arched ballet shoe with a strong shank (#3, or 'Hard' shank) you could check a hardware store for a pre-bent hard strip of metal that could be strapped around the toe box of the pointe shoe and the heel of the shoe could be riveted/glued/strapped/attached in some way to the back of the arch. This would keep the shoe permanently arched. Then using extra elastics or buckled straps you could keep your foot in them.
Have you taken ballet lessons in the past? specifically lessons en pointe? Because if you haven't, make sure when you put this on you wear them for a long time only sitting down, or only with some other support (like holding onto a kitchen counter or something like that.) Because even with that bent-steel piece on that shoe, it's still going to be painful and even potentially permanently damaging to your feet if you don't build up to it gradually. And if you're naturally flat-footed and/or have no arch, this won't be a good idea at all.
Also invest in some really good gel toe inserts and lambswool. And clip your toenails very very short. If you paint your toenails, remove the polish. And be prepared for PAINFUL cramping of the abductor hallucis, the big muscle running down the inside of your foot (your arch). That's going to feel like a paralysis of your whole foot. Blisters on the tips of your toes, and on the upper joints of your toes that will pop and bleed if you don't use sports tape or bandaids to cover those joints. You'll also get cramps up the back of your legs, up your Achilles tendons and leg muscles. If you stand for long periods of time on your toes like this you'll also get back strain and hip pain. All of which will only be that much worse of you're over your recommended weight. And as you get older, if you do this over a period of years, you may get chronic back pain and/or intermittent hip pains.
So think carefully before you do this. As a former dancer, I know how going en pointe can hurt. And that was back when I was ten, imagine how it would feel now, after having had two kids and now with an extra sixty pounds on my frame! I couldn't do it. I've hung up my pointe shoes permanently. If yo can do it, go ahead...but do some basic foot-strengthening exercises first.