What DS AND GBA cart set to get?

I want to get a homebrew kit that I can play on my GBA or DS. IE, be able to play GBA and DS homebrew, on a DS or a GBA. I want to have SD storage rather than onboard flash memory for expandability. Because of this, I have been looking at a slot-2 with a superpass.
I have found a Supercard/Superkey combo from Kickgaming and realhotstuff for $40+s&h.
However, I've heard that slot-1 cards require no patching and have higher compatibility. Is this true? How is the Supercard/Superkey compatibility?
Also, are there any slot-2 devices that work with SDHC?

If anyone finds a lower price for a device that plays GBA and DS homebrew, please reply.
Thank you.

That combo would work well, but keep in mind that the slot-2 Supercards are not the greatest for GBA games. See http://wiki.pocketheaven.com/SupercardGBASlowdowns for more info on that.

Most people get a slot-1 device and a slot-2 expansion pack, but since you want to use this on a standard GBA as well this would not be recommended, as the expansion packs usually don't work well (if at all) without a slot-1 device as well.

Some of your other questions I can't answer due to forum rules, but the only slot-2 device to support SDHC is the M3 Perfect. However, this is not worth using since it only works with media files using the M3's built-in media player, not GBA or DS binaries. It's easier to act as if your max for slot-2 devices is 2 GB per media card.

As far as I'm aware there aren't any slot 2 devices that support SDHC.

If you want the slot 1 compatibility you should either buy a M3DS Real including the GBA RAM expansion pack, or you could buy any other slot 1 device and an ez-flash 3 in1 expanion pack or an ewin expansion pack.

I am not sure about the compatibility of the Supercard, but you shouldn't have much any trouble with the supercard.

You could also get a Slot 1 device and a slot 2 device, but this will probably cost you more than buying one of the RAM expansion packs.

EDIT: Sorry didn't see the post above

Update: Ended up with a Supercard and Superkey, and love em. Still works amazingly.