OOOOOOOOOk guys maybe quite with the slinging match now? It's getting no where, is entirely off topic, if you want to insult/abuse/slander each other go for your lives, but do it elsewhere not on someone's post.
To the OP, No I don't really agree with your way of going about this 'breeding' business, but I'm not going to shoot you down for it, I will simply give my opinion and leave it at that, just to give you something to mull over without having to dredge through 5 pages of 3 people trying to knock each other off their perch.
There is not a great demand for miniatures/shetland's unless they are of superb quality and temperament. And even then, there is still far less demand for them than a riding horse. You CAN breed 'up' for height, but if she's a mini/shettie, you're not going to get something that anyone bigger than a 5 year old kid can ride.
Unless your mare is of fantastic quality, and you pick a suitable stallion, not just any stallion that is cheap and willing to 'give it a shot', there is little point in breeding unless you intend to keep the foal for your own purposes. But even if you did want to breed just for yourself, it is MUCH cheaper and MUCH less stressful to simply go to an auction and purchase a foal, that will probably be of better quality than one you may breed. There are so many unwanted horses going to the doggers due to over breeding, even the quality horses are being dogged because of the lack of demand.
My last words to you: Before you commit to breeding your mare, go onto google, and check out the number of horses being dogged or being sent off the auctions, and check on the reasons WHY there are so many going. It may just change your mind about breeding, save a pony's life rather than breed another one that may await the same fate.