Can you think of longer names for Meri, other than Meredith and Merida?
You can always use Meri as a full first name and do a longer middle name. Usually people do a long middle name and then a short first or vice versa.
here's about 70 names that include Meri.
Girl Names that Contain "meri" at Baby Names Pedia - Page
I like Meri on its own. It's Finnish for 'sea'.
If I have a Merit she'll be nicknamed Merry :)