What Cfgk24 said: I bought a cheapish secondhand DSi XL from the States to run DS-10+ with more voices because Australian DSi's are also not region compatible with the DS-10+ cart. That said I haven't actually got any tracks finished yet that use the extra voices, which is a bit lame... partly on account of not having cleared the purchase of the DSi with the Central Scrutinizer.
DS-10+ is still much much more useful to me than DS-10 on my Lite, because of the programmable track muting and ability to solo over sequences. And you will at least be able to use the original DS-10 cart on a Euro 3DS too - just not DS-10+ on a non-US region DSi.
[Actually, does anyone know if there is a BIOS flash that can overcome this nonsense? Don't want to pirate, just use the software I paid for on an Australian DSi!]