Although I'm pretty sure I'm not the first person to do this, an experiment in creative upgrades was largely successful, so I present an image file of the 18 Feb 2015 release of Minibian, upgraded to Jessie:
http://www.onesource-network.com/downlo ... upport.zip (1.63GB ZIP)
As usual, use Win32 Disk Imager, etc. to push this to the SD card.
Basically I took a clean image of Minibian, expanded the root partition to fit an 8GB card, changed the graphics settings for my 7" LCD (so it'll try to boot to HDMI @ 800x480 resolution - edit /boot/config.txt as required to change this), configured for both British and American UTF localization, added a few things Minibian leaves out (raspi-config, nano, logrotate, htop, and usbutils), and finally upgraded the install to Jessie. Source.list is edited to point to the jessie repos instead of wheezy so apt-get can do its thing. The system responds to ID requests as "Raspbian GNU/Linux 8 (jessie)" and reports its kernel version as 3.18.11-v7+. The PiCam works fine (once enabled with raspi-config) but I haven't tested SPI, I2C, GPIOs, etc. yet so YMMV.
Default login/pass is root/raspberry - be sure to change this ASAP.
This upgrade is set up to use an 8GB card but only consumes about 420MB of storage space, so you have plenty of usable room. It boots to login in roughly 12 seconds, and when idling consumes <40MB of RAM. It's about as bare-bones as you can get. You'll likely need to install and configure additionals like WiFi as needed for your specific application.
Want a version with LXDE already added? Try this image instead:
http://www.onesource-network.com/downlo ... upport.zip (1.78GB ZIP)
It's larger - 1.3GB of storage consumed instead of 420MB - and takes more memory to run - 110MB instead of sub-40M - but it's still shockingly compact for a fully functional graphical OS. It runs nicely on the Pi 2, but I don't know how well it'll run on the single-core Pis since I only have Pi 2s.
I make no claims as to anything ownership-wise aside from my time in setting this up for anyone that is interested. Minibian is not my project so I'm happy to point everyone at https://minibianpi.wordpress.com/ as the original source. Since Jessie is the test branch, don't expect solid guaranteed stability.