Virtual Micro Design propose one the fastest simulator available
today: UMPS.
UMPS includes:  - simulator
                - assembler/disassembler
                - complex component simulator: LCD panel, I2C EEPROM,
serial EEPROM, ADC/DAC, ...

Give it a try:
                    http://www.vmdesign.com
Best regards,
        Philippe.

  +----------------------------------------------------+
  |  Virtual Micro Design                              |
  |  Technopole Izarbel,                               |
  |  64210 BIDART                                      |
  |  FRANCE                                            |
  |                                                    |
  |  Phone: ++33 559.438.458   Fax: ++33 559.438.401   |
  |                                                    |
  | E-Mail: p.techer@idls.izarbel.tm.fr                |
  | URL:    http://www.vmdesign.com                    |
  +----------------------------------------------------+