This is a topic I often have with some of my friends. There are several solutions out there, but (for me) it's been a tough road.
I'm stubborn. I like my A1000's to run 1.3.
Most of the solutions you'll find out there utilize IDE HDD options for Compact Flash, etc.
I recently picked up
one of these, which fly off the shelves when they get restocked. To the shop owner's knowledge no one has publicly stated if they've put one in an A1000. I only got mine a couple of days ago and haven't had a chance to install it.
It would provide plenty of internal Fast RAM and provide a speed boost (not really critical to me, to be honest). But this board claims it can run 1.3 which is why I decided to get it. I do not yet know if a CPU relocator will be necessary for it to fit (my guess is yes but I don't know for sure).
That all being said, I rather love my external solutions that I'm currently running. They work flawlessly. I have a fully souped up Starboard 2 that has 2MB RAM, a janky but functional (if wrong) RTC, and SCSI port. Via the SCSI port I have a SCSI Zip Drive (100mb) which semi-autoboots off 1 single floppy. Plus, this wacky setup provides a nice table for the external second FDD.
This machine also has a Rejuvenator, so we get the 2mb Chip RAM and KS 1.3 ROM.
But that's a bizarre setup, I know.
The board above might deserve your research as well as the
Wicher 500i, which is also an internal solution if you don't mind using one of EzdineG's Amiga 1000 KS ROM boards (found on this site) and OS 3.1.
No black and white easy answers, really, but the Amiga 1000 is a diva after all.
My favorite internal RAM solution is the MKL 68000 RAM board (8MB) which is affordable and well-built. And I've got a couple of ADspeed accelerators which also stack above the CPU, but mine only work after workbench has booted and the software launched. The manuals say it should work all of the time via a jumper, but mine don't (sigh).