Just use the TabControl on your 'main form'. You can easily add tab pages at runtime.
tabControl1.TabPages.Add("New Tab");
Carry on using a form for your 'device'. You can place an entire form inside a tab control ...this code will create a new instance of a form and place it in the last tab of a tab control:
frmDevice dev = new frmDevice();
dev.TopLevel = false;
dev.FormBorderStyle = FormBorderStyle.None;
dev.Parent = tabControl1.TabPages[tabControl1.TabCount - 1];
dev.Dock = DockStyle.Fill;
dev.Show();