Hi,
I once used a BeoCom 4 for my company, and had to give up after one month, swapping it for a Jacob Jensen T80 phone that I had at home ; actually, the BeoCom 4 became ideal for home, while the Jensen one became perfect for office use!
I think the only viable option for office use would be the BeoCom 6000 , not everybody can use BC4 or BC2. The new BeoCom 5 is great because it has a speaker option, quite useful for conference calls & meetings.
However, mixing corded and cordless phones might be tricky, since the BeoLine base handles the whole phonebooks, so the corded phone would have a different phonebook all the time I guess..
Reunion Island is greeting you!