Expanding the color TI-84+ calculator into a full computer

[Joseph_21sv]

Inspired by the MEGA65 open computer and the color TI-84+ calculators, I had this idea for the minimum requirements for an ultimate Z80 computer:
CPU: simulates performing at least one "real" operation on an 18.32MHz Z80 (does not strictly imply using an eZ80, but the eZ80's specifications allow the most room for optimization)
Video: VGA 1024x576x16bpp (102.4 MHz dot clock), 16-bit master palette, variable chroma sampling rate, vertical/horizontal/ diagonal smooth hardware scrolling, hardware parallax scrolling, hardware split-screen scrolling, 64 sprites on screen (8 per scanline), 8x8/8x16/16x16 hardware sprite size (up to 32x32 by integer zooming), 8x8 tilemap playfield with hardware tile flipping
Audio: 1xAY-3-8910 compatible, stereo
DMA controller
512KiB base RAM (does not strictly imply using an eZ80, but the eZ80's 24-bit address mode will dispense with the need for external memory management)
Semi-compiling structured "floating"-point BASIC interpreter in ROM (not necessary for this to be in any part object-oriented, but it would be interesting)
USB (and Micro USB) I/O
10/100 Mbit Ethernet