Janome 6600 and 6500 have 9-1/2" harps; the 6600 probably costs more than your budget new but you might luck out on a 6500 for around that price. Or look for either of them used.
I have the 6600 and it's a great machine. It's high shank so probably can't use the feet from your 3050 but the bobbins, at least, will be interchangeable.