Here's a link;
http://www.newegg.com/Product/Product.aspx?Item=N82E16834100125
It comes with leopard, but you should be able to upgrade to Lion/Mountain Lion despite it being an older model. It won't be a speed demon, but it should handle what you want. That's $430 + your $99/yr subscription + the cost of Mountain Lion. You can't download it from the App Store on leopard, so you'd have to work that out. Someone somewhere told me that you can buy Lion (so I would presume the same with Mountain Lion now) at the Apple Store and they will install it for you, since you won't have access to the app store. Otherwise you'd have to first upgrade to snow leopard, THEN upgrade to at least Lion to get the latest version of Xcode.
http://www.newegg.com/Product/Product.aspx?Item=N82E16834100125
It comes with leopard, but you should be able to upgrade to Lion/Mountain Lion despite it being an older model. It won't be a speed demon, but it should handle what you want. That's $430 + your $99/yr subscription + the cost of Mountain Lion. You can't download it from the App Store on leopard, so you'd have to work that out. Someone somewhere told me that you can buy Lion (so I would presume the same with Mountain Lion now) at the Apple Store and they will install it for you, since you won't have access to the app store. Otherwise you'd have to first upgrade to snow leopard, THEN upgrade to at least Lion to get the latest version of Xcode.