1:- Bluetooth support
Only requiers a bluetooth stack, BT is typically available via USB.
2:- USB
Covered already, I would say
3:- updated OS
Or truly free OS3

4:- Fast Ethernet
And ethernet for all models

5:- Nvidia graphics.
This one I really dont grasp.
6:- Switchable CPU system backwards compatible to Amiga OS1.3
The CPU is rarely the problem - chipset usually is.
7:- IDE/SATA
SATA controller would be nice, howeved Deneb already does this via USB, and ACard has SCSI/SATA adapters. Cheap SATA/ATA adapters can be bought everywhere.
8:- Amiga sound, but in modern format
What is "amiga sound"?
9:- VGA and 15Khz output
We really dont need 15KHz much, and VGA is soon gone. DVI/HDMI is much more needed.
10:- Minimum 64mb Chipram (if needed)
Best would be to eliminate the need of chipram.
11:- Minimum 512mb Fastram

12:- CPU well where do you start with that?
68k CPU? FPGA! PowerPC?
13:- A first class web browser.
I think OWB already is a good start for that!
Or am I just walking in dreamland here yet again?
Nah! But I was pondering on whether you wish for OS4 or Classic here
