Vytvor si klasicky UserControl cez pridanie súboru a potom je to jednoduché, podedíš vlastnosti a udalosti :

public partial class TButton : UserControl
{
    private bool ishover = false;

	protected override void OnClick(EventArgs e)
	{
	   base.OnClick(e);
	}

    protected override void OnMouseMove(MouseEventArgs e)
	{
       if (!ishover)
       {
           ishover = true;
           this.Invalidate();
       }
       base.OnMouseMove(e);
    }

    protected override void OnMouseLeave(EventArgs e)
	{
       if (ishover)
       {
           ishover = false;
           this.Invalidate();
       }
       base.OnMouseLeave(e);
    }

    protected override void OnPaint(PaintEventArgs e)
	{
    	Graphics g = e.Graphics;
    	g.FillRectangle(new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, this.Width, this.Height), (ishover ? Color.Gray : Color.Silver), Color.WhiteSmoke, System.Drawing.Drawing2D.LinearGradientMode.Vertical), new Rectangle(0, 0, this.Width, this.Height));
		SizeF TextSize = g.MeasureString(this.Text, this.Font);
		g.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), this.Width / 2 - TextSize.Width / 2, this.Height / 2 - TextSize.Height / 2);
	}
}

Aplikáciu spusti / prekompiluj a v design móde - v zozname komponent - Vlastné komponenty sa ti objaví TButton (ten prenesieš ako klasický button na plochu formulára a to je všetko).