Hi there! From Icom USA comes this mod sheet for the 2700H:
 
RX Expansion Modification
=========================
1.  Remove Top Cover. (6 Screws)
2.  Remove Bottom Cover. (6 Screws)
3.  Remove Front Display. (4 Screws)
4.  Locate the Logic Board.
5.  Remove W1 from the logic.
6.  Hold [SET], [SPCH] and turn radio on.
 
Expanded Frequency Range
 
AM Mode   118-136 MHz
FM Mode   138-174 MHz
          350-470 MHz
 
Tx Expansion Modification
=========================
1.  Remove D16 and D17
2.  Hold [FUNC], [A], [CLR] and turn the radio on.
 
FM Mode   138-174 MHz
          350-470 MHz
 
------------------------------------------------------------------
 
That's what Icom's sheet said.  I didn't follow it when I modified my
radio and it worked very well.  Here's what I did:
 
1.  Remove power and antenna from the rig.
2.  Remove the face plate from the rig (careful with the small hookup cable
    that attaches to the logic board).
3.  Locate the "Zero-Ohm Resistor" W1 and cut it out with a fine-tipped set
    of wire cutters.  W1 is clearly marked on the board and is along the top
    edge, just to the right of center of the logic board.  In my rig, W1
    looked like a 1/8 Watt resistor, solid white in colour.
4.  Using the same pair of fine-tipped cutters, remove D16 and D17.  They're
    the first two diodes slightly below W1, going towards the LEFT side of
    the rig.
5.  Carefully re-attach the face plate, mic, antenna and power.
6.  Press SET and SPCH together and power on the rig.  Keep the buttons
    depressed for about 4-5 seconds as the radio goes through a reset.
    ALL MEMORY INFORMATION IS LOST!!!.
7.  Re-program in your memories and there you have it!
 
Futile Attempt at a diagram:
 
Front View with face plate detached.
________________________________________________________________________
|                                        DDDDD W                       |
|                                                                      |
|                                           D67                        |
|                                               ____                   |
|                                              |HEAD|             ___  |
|                                               ~~~~             |MIC| |
|______________________________________________________________________|
 
Where D = Surface Mount Diode Package
      W = Jumper W1
      6 = Diode D16
      7 = Diode D17
   HEAD = Face Plate Connector
    MIC = Mic Connector
 
I hope that the diagram and description are clear enough to follow.
 
For X-Band repeating, the only information that Icom game me was a brochure
entitled "With Icom Radios, Crossband Repeating Has Never Been Easier!" In
short, the only way I've been able to find to get the 2700 to x-band repeat
is to put it into remote mode and use the appropriate DTMF code to turn it on.
It works fine in this mode.  I've done extensive testing and all these
functions appear to work fine:
 
DTMF CODE                         FUNCTION
=========                         ========
B, XXX, #                 Remote function ON (XXX = 3 digit password)
B*                        Remote Function OFF
DB*                       Cross Band Repeat ON
DB, XXX, #                Cross Band Repeat OFF (XXX = 3 digit password)
1                         Call
2                         Memory
3                         VFO
6                         High Power
9                         Low Power
DC                        Speech
D (+NNN)                  Enter (Direct entry of mem. chan. or VFO Frequency)
#                         Up
*                         Down
A                         Clear
 
That's all the information I've got to date.  So far, I haven't been able
to find a method of putting the rig into X-Band repeat without using the
remote control function.  It'd be nice to be able to do that from the rig
or mic.
 
Hope this information helps!
 
73
 
Ray Semenoff  VE6RHS
Chief Engineer (and Bottle Washer)
CJSR FM
University of Alberta
Edmonton, Alberta, CANADA.