I agree the default 737 panel is horrible, espcially when they are on NG 737's, with the glass cockpits, and dont look anything like the default panel
I'm not sure about A380 or MD88 but the best freeware 737-700 panel there is can be found here
http://www.projectopensky.com/downloads.php?aircraft=o8vb1&location=panelpackage
Its from the posky website, but can be used with any plane. It is designed for the 737ng series (737-600, -700, -800, -900)
Here's a screenshot I took of it a while ago, found it in my photobucket account
Go to your 737-700c folder, look in panel, it just contains a 1kb panel.cfg file that aliases the panel to the default 737-400. Just follow the instructions in the download above, you will need to overwrite the panel.cfg as well as add a few .bmp files (included in download, read the readme)
Hope this helps
Tim