What Is A Good Long Range Cordless Phone?
I have a work shop that is about 25 yards away from my house. The cordless phone I now have will work within about 10 yards of the shop. Is there an extended range phone that will work better and possibly even work inside the structure?

all phones, by FCC rules and regulations, are limited in power.
So as a result, you must work around this limitation. The phones base unit needs to be as close to the remote receiver as possible. Also, you need to limit attenuation from walls, trees, plants, so try to put the base as high in the house as possible, closest to the workshop.
Another thing is noise.
There are a ton of other devices that share the same radio bands as the cordless phones. This would indicate that you need to get the NEWEST technology as possible. 5.8GHz is the latest, but 5.8GHz is very line of sight and very suspectable to attenuation. 900MHz is very old (in the phone world), and most everyone has moved off 900MHz, but finding a new 900MHz phone would be impossible. Forget 1.2GHz and 2.4GHz, you will be competing for signal with every noise generating wireless computer device.
So, for now, the 5.8GHz or the 1.9GHz DECT phone is the best of a bad situation.
Contrary to many beliefs, all cordless phones have basically the same range. They are all limited to 100mw. power, (one tenth of a watt), and are limited in range, especially by home construction, wood, metal, wires, etc. between the home base and handset. I have tried 900 Mhz., 2,4 Ghz., 5,8 Ghz., and DECT..(ecch,,hype.!) at 1900 Mhz. A few extra feet was obtained by the 900 Mhz., but overall performance and range still limited. The best range is obtained with no obstructions between the units. (Your best fix, would be to get ‘Call Forwarding’ from the phone company, then forward your home or office calls to your cell phone when you are away in the shop, or wherever..)
Regular cordless phones are inherently designed to use a frequency that is very limited in terms of range. If you want a longer range cordless, you should try a cordless that uses VHF frequency. You can find them at http://www.longrangephones.net These type of cordless gives you so much range that you can bring it along like a cell phone. So visit the website and check it out.
Why dont you check out this site: http://www.primetimetelecoms.jp
I saw one for : Radio range: 50 meters (160 ft) They are offering a cordless USB voip IP Phone for international calls ..am not sure if thats what you want… It looks cheap as they said you only need to just top up your account and have both the credits and the phone..
Different phones are available with different frequencies.
check them out
Just Please be aware that phones from web site : http://www.longrangephones.net are clones – fakes products from China and also they have very low quality and short live
You can see how original Senao products look on http://www.senao.com or on http://www.cordless4u.com/cordless.htm