I did a search for 2005 Ford Focus Speedometers and it gave a list, all of which start with 4S4T-10849. My guess is that they would all be interchangable. You probably only want MPH, so that narrows the list down to 3 series.
Select one at a time and look through the list for a description which specifies that it has a tach. A few I found for your model are:
Under BC-BJ I found:
2005
Speedometer(See also Instr. Cluster)
Ford Focus 5DR-HB,GRN,3-05,TACH ,TRIP,CK-ID A 060449 $125 Venice Auto Parts USA-PA(Philadelphia) E-mail 1-800-523-1600
Under FE-FJ I found:
2005 Speedometer(See also Instr. Cluster)
Ford Focus SE, 2.0L,AOD,140 MPH,W-TACH A 6J5823 $100 AAA Auto Salvage - QRP Partner USA-MN(Rosemount) E-mail 1-800-238-6664
Under HE-HJ I found:
2005
Speedometer(See also Instr. Cluster)
Ford Focus -HIGH SERIES,TACH,140MPH 1617 $85 East Side Auto Parts USA-MI(Ravenna) Request_Quote 1-866-259-0111 Request_Insurance_Quote
You could try calling one of those places. They might not be able to tell you anything about it, since it's probably a salvage yard and they'd have to go pull it first. The best bet for you is probably getting the one under the BC-BJ or FE-FJ category. I'm not sure exactly what "HIGH SERIES" means so I'm not as confident the last one would work.
When I got mine, I called them up and was able to pay with a credit card over the phone and they shipped it out that day. Just make sure you can return it in case it doesn't work. Worst case scenario you'll have to pay a shipping fee, plus maybe a couple bucks "re-stocking"