NAS (with RAID capabilities)

For all you hardware and IT specialists out there.

I'm looking for a solution to use some dust catching (but working) HDD's.

My idea would be to get a HDD tower case (preferrably RAIDable and [maybe, not neccessarily] with NAS functionality in-built) and add some HDD's to be used on my LAN (the tower could be added to my router through USB as well).

The HDD's i have available are 1x 1TB, 2x 500GB, 1x 250GB (and some more with 160GB, 120GB and 80GB)

Is there a hardware solution that lets me add, lets say the 1TB and the two 500GB HDDs and RAID them as one 2TB accessible NAS?

All of the HDD's are either 7200 or 5400 rpm so i could live with all of them running at the lowest speed.

I also know that (at least earlier) RAID solutions assumed the existance of HDDs with the same size (otherwise they would cut all down to the lowest size to be able to RAID), but i'm not sure if this is still the case (and i also don't remember if that was a restriction of the diffrerent RAID versions).
If there would be a loss of some MBs (to level out the three HDDs) i could also live with, but not if it would cut the 1TB drive into half.

Thanks in advance

EDIT:
All of the HDDs are SATA

I think what you are looking for is JBOD. It's not a RAID but just concatenates all drives into one big volume. Every HDD case with RAID functionality should be able to do this. Just make sure that the description mentions it.

You should be aware that without any redundancy, if one of the drives dies the whole array will be lost. So better make backups.

@thomas

I just realized i never answered...sorry.

Thank you for the hint.

I took an easier route though, got a 4-HDD mini tower and plug/play with it whenever i need to.
It's too loud (fan not switchable) and draws too much energy (does not power down on either PC/Amiga or NAS) for 24/7 use.

But at least they have a home now and are used sporadically